User's Manual
Table Of Contents
- 1 Overview
- 2 GE864-QUAD V2 Mechanical Dimensions
- 3 GE864-QUAD V2 module connections
- 4 Hardware Commands
- 5 Power Supply
- 6 Antenna
- 7 Logic level specifications
- 8 Serial Ports
- 9 Audio Section Overview
- 10 General Purpose I/O
- 10.1 GPIO Logic levels
- 10.2 Using a GPIO Pad as INPUT
- 10.3 Using a GPIO Pad as OUTPUT
- 10.4 Using the RF Transmission Control GPIO4
- 10.5 Using the RFTXMON Output GPIO5
- 10.6 Using the Alarm Output GPIO6
- 10.7 Using the Buzzer Output GPIO7
- 10.8 Indication of network service availability
- 10.9 RTC Bypass out
- 10.10 External SIM Holder Implementation
- 11 DAC and ADC section
- 12 Conformity Assessment Issues
- 14 Document Change Log
GE864-QUAD V2 Hardware User Guide
1vv0300841 Rev.0.1 24/11/09
Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved page 42 of 65
9.1.2 Input Lines Characteristics
“MIC_MT” 1st differential microphone path
Line Coupling AC*
Line Type Balanced
Coupling capacitor ≥ 100nF
Differential input resistance 50kΩ
Differential input voltage ≤ 1,03V
pp
(365mV
rms
)
Microphone nominal sensitivity -45 dBV
rms
/Pa
Analog gain suggested + 20dB
Echo canceller type Handset
“MIC_HF” 2nd differential microphone path
Line Coupling AC*
Line Type Balanced
Coupling capacitor ≥ 100nF
Differential input resistance 50kΩ
Differential input voltage ≤ 65mV
pp
(23mV
rms
)
Microphone nominal sensitivity -45 dBV
rms
/Pa
Analog gain suggested +10dB
Echo canceller type Car kit hands-free
(*) WARNING: AC means that the signals from microphone has to be connected to input lines
of the module by a CAPACITOR, which value must be ≥ 100nF. Not respecting this constraint,
the input stage will be damaged.